See Forecasts for More Time Periods
Where: This change applies to Lightning Experience and Salesforce Classic in Professional, Performance, and Developer editions and in Enterprise and Unlimited editions with the Sales Cloud.
Why: In Display Settings on the forecasts page, forecast users can set a wider forecast range.
How: No steps are required to give your team this enhancement. To widen the default forecast period, select the number of months or periods on the Forecasts Settings page in Setup.