Next, select the Fiscal Year Variant and Group Currency, which are applied to the entire system and cannot be changed after saving.
The Fiscal Year Variant (FYV) defines the relationship between the calendar year and the fiscal year. This selection defines how the system determines the posting period to assign when posting a journal entry. In accounting, you can have a fiscal year with a maximum of 16 posting periods, including special periods. The same FYV applies to your entire system with all its ledgers and company codes.
The Group Currency is the global currency that is applied to the entire system. A group currency allows you to compare amounts from different company codes in their respective currencies against one, overarching currency. You can define the currency for each company code and ledger in the Product-Specific Configuration phase with the configuration activity, Define Currency Settings for Ledgers and Company Codes.

Find additional details about financial settings in this SAP Blog: What you need to know about Finance in SAP S/4HANA Cloud Public Edition.