Can I upload a file to website via API?

Hi
In order to support Universal Links, we need to upload a file to website and then get it with a following URL
https://<<mydomain>>/my_file
or
https://<<mydomain>>/.well-known/my_file
I am wondering if there is a way to do it via API ?
If impossible, Can I do it on backoffice?
Best regards,
Steven
Post edited by steven_chang on