IMG > Financial Accounting > Financial Accounting Global Settings > Document> Posting Periods > Define Variants for Open Posting Periods

In this activity you specify for each variant which posting periods are open for posting in SAP. Two intervals are available for doing this (period 1 and period 2). For every interval, enter a lower period limit, an upper period limit and the fiscal year.
You close periods by selecting the period specifications so that the periods to be closed are no longer contained.
You can copy the settings from existing company codes delivered by SAP as follows:-

Replace all 0001 with 9100