Ancestry.com does not allow upload of DNA raw data
downloads of your DNA data only; no uploads of DNA data or gedcom
If you have tested at FamilyTreeDNA: https://learn.familytreedna.com/autosomal-ancestry/universal-dna-matching/may-download-family-finder-raw-data/
Free upload; fee for chromosome browser: https://www.familytreedna.com/autosomal-transfer
Upload your gedcom: https://learn.familytreedna.com/myftdna-user-guide/pedigrees-gedcoms/
Upload DNA help: https://www.gedmatch.com/Include/UploadHelp.php
Upload Gedcom: https://www.gedmatch.com/v_upload_gedcomx.php
only uploads of DNA and gedcom, no downloads of either, although you can download analysis data
Uploading DNA data is free; however you will not have all the features of those who test there.
Uploads of both DNA data and gedcoms are free. With a paid membership you do get tree matching! This is one of the most used European sites, so DNA matching is very valuable if your ancestry is mostly European.
Upload/Download gedcom: https://my.geneanet.org/arbre/
DNA Painter does not accept DNA raw data as the above sites do; rather it accepts segment data in a .csv format. Extensive help to get the information in the correct format here: https://dnapainter.com/help/import
Be sure to visit the Tools page: https://dnapainter.com/tools often as more tools are added.
For the Ancestral Trees function, begin at https://dnapainter.com/#trees
WikiTree does not accept DNA raw data uploads, but does make it possible to link tests and results to the tree. Limited gedcom uploads are accepted, however people are not added to the common tree without extensive searching for duplicates. Like FamilySearch Family Tree, WikiTree is collaborative. The privacy of living people is protected while still allowing collaboration.
To get started: https://www.wikitree.com/wiki/Help:How_to_Use_WikiTree
Where you cannot download/upload DNA data or gedcoms
No DNA or gedcoms can be uploaded to 23andme
You can get information in and out of FamilySearch FamilyTree, but besides https://www.familysearch.org/mytrees/ really only through supported genealogy programs.