Is it possible? MAYBE if your website directory was also set up as a drive letter (Z:) or network share (//WEBSERVER). There are tools that can do this.

BUT YES, THIS IS DISCOURAGED.

If you want to put your data online, my recommendation is SQL Server. It's inexpensive and not terribly difficult.

This can be done if your online database is SQL Server.  See picture below.  All my linked tables are from a Winhost online SQL Server database.  My Access front end can access them like any other tables.

If you mean to do this with an Access database, you can upload it, but you can only have access to it server-side.  That means all database operations have to be done with server-side coding such as ASP and VBScript (which Richard has lessons on).  And you can't link tables in your front end, because that is a client-side action.  In addition, Access databases are less secure online.  So most people don't go this route.

Winhost specifically says you are allowed to upload Access databases (see picture below).  But again, this only means you have access on the server-side, not on your local front end.  Winhost does not state this clearly, and assumes the user knows this already.

Yeah 20 or so years ago when I first started dabbling with getting my Access databases online, I did try to upload a back end to the website and I was able to code it fine using ASP. But only for the website (server-side, as Kevin says). I would still have to use tricks to transfer data back and forth because your local front end Access database can't connect to a back-end Access database. I played around with using a VPN and mapping a drive letter that way, but it's not a good idea.