Yes, sorta. https://accountants.intuit.com/support/en-us/help-article/customer-list/print-mail-labels-lacerte-cl...

Lacerte does have slip sheets that can be used with window envelopes. This is probably the easier method. You can print a slip sheet with each return Settings > Options > Tax Returns > Tax Return Options > Return Mailing Slip Sheet (Option: Format the client invoice to work in the window you have and send that invoice with each return as the Mailing Slip Sheet)