The most obvious and easiest way to get your Walmart MasterCard monthly statement in the mail rather than electronically is by calling Walmart MasterCard customer service number at 18883316133 in Canada. Let them know that you would like to switch from Electronic statements paperless to physical paper statement in the mail. They will ask you personal verification questions to verify that it is you calling and not someone scaming under your name.
The other way to do the changes online without calling customer service is by logging into your Walmart MasterCard online account first. On the bottom left hand side you will find under "My Profile" tab, "Go Paperless". Alternatively, on top right corner, click on "Profile". Click on "Go Paperless". Under "eCommunications options" tab, uncheck the box "Go Paperless". Click on "Submit". There you are done now. You will receive an email telling you that your changes have been made and it will take some days before it takes effect.