Procedure:

Step 01: Log in to your Wix account and go to the Dashboard.

Step 02: Click on the gear icon and select Site Settings from the drop-down menu.

Step 03: Click on the Domains tab and then click on the Advanced Settings button.

Step 04: Scroll down to the DNS Settings section and click on the Add Record button.

Step 05: In the Add DNS Record window, select TXT from the Type drop-down menu.

Step 06: In the Name field, enter @

Step 07: In the Value field, enter the SPF record you want to add.
For example: v=spf1 include:spf.wix.com ~all

Step 08: Click on the Save button.