This may be a stupid question, but I often see academic papers where all the tables and figures are placed at the end of the document. Instead, throughout the text, you'd see these centralized rectangular brackets saying 'Insert Table X here'. I was wondering how to do this as well?
Right now, I have included all the tables and figures at the end of the document, but was wondering how to get the 'Insert Table X here' in the main text.

endfloatpackage. See How to tell LaTeX to place all figures at the end of PDF file? (possible duplicate) or How to place all floats (tables in particular) at a certain point in the document. – Werner Feb 10 '20 at 19:58