For Python on Windows 7, the best version you may use is 3.8 or earlier versions. For Python 3.8, this is actually the last version that will be supported officially on Windows 7 and thus is going to work pretty nicely and updated appropriately. Of course, you could install one or more of the newer Python versions, like Python 3.9 and all other newer versions, but are not officially supported, so they might sooner or later be problematic or miss out essential features.
Therefore, if you are on Windows 7, Python 3.8 should be used as it provides compatibility and ease of access. You can download the same from the official website of Python.