A family of Microsoft relational database management systems designed for ease of use.
Which version of MS 365 do you have? Most include Access, but not all. Does YOUR specific version state that it does include it?
Note that Access is a desktop application. It runs under Windows, so it has to be installed on your computer. Unlike Word, Excel and other Office apps, it does not have a browser based version.
Also, you didn't specify whether you have a PC or a Mac.
Again, Access runs only an Windows. If you have a Mac, you can't install it. However, there are Windows emulation applications for the Mac. You can install one of those and run Access in that Windows emulator, if that's appropriate.