The colors are wrong on my mailer!

If you want the colors on your printed mailer to be as accurate as possible, you will need to use a CMYK Color Palette. 

To make a long story short, the total number of colors that are available for print are less than what a digital screen can render. 

If you designed a mailer in Canva, using any of the available RGB colors, those colors may or may not be accurately represented when the product is ultimately printed.

Designing in Canva
You can get around this issue by creating a CMYK color palette to use in Canva.

Instructions

Designing in Photoshop, etc
To learn more about RGB vs. CMYK and to learn about how to edit your photographs in the CMYK color space in photoshop and other programs:

click here