AWEbase allows you to upload a variety of different file types, depending on what you're trying to do.
Deliverable review assets
Image Files: JPG, PNG, JPEG, GIF
Video Files: MP4, MOV, AVI, WMV, M4V
Audio Files: AIFF, AIF, MP3, WAV
3D Files: GLB, OBJ, STL, FBX
Text Files: PDF
Any other types of files will appear as "generic" files on the review tab. While you can make general comments regarding a generic file, it can't be marked up or annotated.
When you upload a Deliverable reference file, all types of files are accepted, but only JPG and PNG files will appear as previews. Other file types need to be downloaded.
When you submit a Deliverable file, you may upload any type of file.
When you add a new contract template, you may only upload DOCX files.
Note: Testing has shown that when Pages documents with numbered lists are exported as DOCX files, their lists may become mis-formatted. (One possible work-around is to copy the contract from Pages, paste it into a Google Doc, and export it from there into DOCX.)
File size limits
Note that you can set the maximum size limit for each type of uploaded file, as described here.