A:Answer Web site here:
https://www.usa.canon.com/internet/portal/us/home/products/details/printers/megatank-inkjet-printers/all-megatank-inkjet-printers/pixma-g6020#Z7_MQH8HIC0L88RB0AMD0F1Q42OR1
says:
Paper Sizes
3.5 x 3.5, 4 x 4, 4 x 6, 5 x 5, 5 x 7, 7 x 10,8 x 10, Letter (8.5x11), Legal (8.5x14), U.S. #10 Envelopes
US#10 envelopes are supported.