Excel 365 refers to the subscription version of Excel. Non subscription versions of Excel are Excel 2019, Excel 2016, etc. Excel 365 is a part of Microsoft 365 (formerly Office 365.  One of the many benefits of being a subscription services is that updates and new features downloaded and included in your version automatically. Excel 2019, etc. are fixed as to the components and are never updated. A purchase of a newer version would be required.

Excel 365 is the inspiration of this website’s name Excel365Solutions.com

One key thing to understand is that Excel 365 has new features that may not yet available in any other version of Excel. One great example is Dynamic Array Functions, which includes new functions like FILTER, UNIQUE, SORT, SORTBY, SEQUENCE, RANDARRAY, XLOOKUP and XMATCH