Full disclosure, I am one of the maintainers of pdfminer.six. It is a community-maintained version of pdfminer for python 3.
Nowadays, pdfminer.six has multiple API's to extract text and information from a PDF. For programmatically extracting information I would advice to use extract_pages(). This allows you to inspect all of the elements on a page, ordered in a meaningful hierarchy created by the layout algorithm.
The following example is a pythonic way of showing all the elements in the hierachy. It uses the simple1.pdf from the samples directory of pdfminer.six.
from pathlib import Path
from typing import Iterable, Any
from pdfminer.high_level import extract_pages
def show_ltitem_hierarchy(o: Any, depth=0):
    """Show location and text of LTItem and all its descendants"""
    if depth == 0:
        print('element                        fontname             text')
        print('------------------------------ -------------------- -----')
    print(
        f'{get_indented_name(o, depth):<30.30s} '
        f'{get_optional_fontinfo(o):<20.20s} '
        f'{get_optional_text(o)}'
    )
    if isinstance(o, Iterable):
        for i in o:
            show_ltitem_hierarchy(i, depth=depth + 1)
def get_indented_name(o: Any, depth: int) -> str:
    """Indented name of class"""
    return '  ' * depth + o.__class__.__name__
def get_optional_fontinfo(o: Any) -> str:
    """Font info of LTChar if available, otherwise empty string"""
    if hasattr(o, 'fontname') and hasattr(o, 'size'):
        return f'{o.fontname} {round(o.size)}pt'
    return ''
def get_optional_text(o: Any) -> str:
    """Text of LTItem if available, otherwise empty string"""
    if hasattr(o, 'get_text'):
        return o.get_text().strip()
    return ''
path = Path('~/Downloads/simple1.pdf').expanduser()
pages = extract_pages(path)
show_ltitem_hierarchy(pages)
The output shows the different elements in the hierarchy, the font name and size if available and the text that this element contains.
element                        fontname             text
------------------------------ -------------------- -----
generator                                           
  LTPage                                            
    LTTextBoxHorizontal                             Hello
      LTTextLineHorizontal                          Hello
        LTChar                 Helvetica 24pt       H
        LTChar                 Helvetica 24pt       e
        LTChar                 Helvetica 24pt       l
        LTChar                 Helvetica 24pt       l
        LTChar                 Helvetica 24pt       o
        LTChar                 Helvetica 24pt       
        LTAnno                                      
    LTTextBoxHorizontal                             World
      LTTextLineHorizontal                          World
        LTChar                 Helvetica 24pt       W
        LTChar                 Helvetica 24pt       o
        LTChar                 Helvetica 24pt       r
        LTChar                 Helvetica 24pt       l
        LTChar                 Helvetica 24pt       d
        LTAnno                                      
    LTTextBoxHorizontal                             Hello
      LTTextLineHorizontal                          Hello
        LTChar                 Helvetica 24pt       H
        LTChar                 Helvetica 24pt       e
        LTChar                 Helvetica 24pt       l
        LTChar                 Helvetica 24pt       l
        LTChar                 Helvetica 24pt       o
        LTChar                 Helvetica 24pt       
        LTAnno                                      
    LTTextBoxHorizontal                             World
      LTTextLineHorizontal                          World
        LTChar                 Helvetica 24pt       W
        LTChar                 Helvetica 24pt       o
        LTChar                 Helvetica 24pt       r
        LTChar                 Helvetica 24pt       l
        LTChar                 Helvetica 24pt       d
        LTAnno                                      
    LTTextBoxHorizontal                             H e l l o
      LTTextLineHorizontal                          H e l l o
        LTChar                 Helvetica 24pt       H
        LTAnno                                      
        LTChar                 Helvetica 24pt       e
        LTAnno                                      
        LTChar                 Helvetica 24pt       l
        LTAnno                                      
        LTChar                 Helvetica 24pt       l
        LTAnno                                      
        LTChar                 Helvetica 24pt       o
        LTAnno                                      
        LTChar                 Helvetica 24pt       
        LTAnno                                      
    LTTextBoxHorizontal                             W o r l d
      LTTextLineHorizontal                          W o r l d
        LTChar                 Helvetica 24pt       W
        LTAnno                                      
        LTChar                 Helvetica 24pt       o
        LTAnno                                      
        LTChar                 Helvetica 24pt       r
        LTAnno                                      
        LTChar                 Helvetica 24pt       l
        LTAnno                                      
        LTChar                 Helvetica 24pt       d
        LTAnno                                      
    LTTextBoxHorizontal                             H e l l o
      LTTextLineHorizontal                          H e l l o
        LTChar                 Helvetica 24pt       H
        LTAnno                                      
        LTChar                 Helvetica 24pt       e
        LTAnno                                      
        LTChar                 Helvetica 24pt       l
        LTAnno                                      
        LTChar                 Helvetica 24pt       l
        LTAnno                                      
        LTChar                 Helvetica 24pt       o
        LTAnno                                      
        LTChar                 Helvetica 24pt       
        LTAnno                                      
    LTTextBoxHorizontal                             W o r l d
      LTTextLineHorizontal                          W o r l d
        LTChar                 Helvetica 24pt       W
        LTAnno                                      
        LTChar                 Helvetica 24pt       o
        LTAnno                                      
        LTChar                 Helvetica 24pt       r
        LTAnno                                      
        LTChar                 Helvetica 24pt       l
        LTAnno                                      
        LTChar                 Helvetica 24pt       d
        LTAnno                                      
(Similar answer
here,
here and
here
, I'll try to keep them in sync.)