Yesterday I saw that there is a new (new to me at least..!) type of column (formerly attribute) which you can create in any customizable table (formerly entity) which can be used to upload file.
You can create multiple file type columns in a table and upload one file in one column.
I create a new column called Document in account table as shown below from power app maker portal.
Same can be created from classic interface as well:
More importantly it’s not visible in classic form editor to add onto account form So better to use power app maker portal to do any customization :
Then i uploaded a sample txt file in my Document column on account record:
Playing around rest api to download the file:
I hit the below url from postman and in body got the content of the file.
For more details on the same, please check https://docs.microsoft.com/en-us/powerapps/developer/common-data-service/file-attributes