Tutorial
You can edit existing banners and add new ones or edit the text your affiliates will see.
Edit Banner
1. Under 'Commerce' choose 'Affiliate Program'
2. Choose 'Edit Affiliate Banner' from the Affiliate Menu
3. Select 'Add New' to add a new banner, or click 'Edit' next to the banner to update
Edit Text Links
1. Under 'Commerce' choose 'Affiliate Program'
2. Choose 'Edit Affiliate Marketing Page' from the Affiliate menu
Below is an example of the text in "Text Link Phrase" text and the second image is how the affiliates see it in the Affiliate Conrtol Panel
You can edit that text as you wish via the "Edit Affiliate Marketing Page"
If you want to edit where the affiliate text links point to, you would manually edit the link in the href part.