Question On licensing

Sorry for the dumb q's. I am new to the F5 platform. Do I have to have a cloud edition license in order to run F5 in a public cloud? I am thinking of taking the license's I no longer use on prem, but all of the docs around pubilc cloud just talk about cloud edition? Also what is involved with changing the license on an existing F5 virtual edition? I need to upgrade one of my pairs to a best license, but I have not been able to find a doc on how to do it. Thanks