Custom Coding for Member Areas

Is it possible to change some of the built-in text in the Member Areas with custom coding? If so, how? For example, at checkout it says "Member Summary" but I'd like to change it to "Purchase Summary". Or in the attached screenshot where it says, "Membership Confirmed" and "View Member Area" - change it to "Purchase Confirmed" and "Go to Tour". Basically, I want to utilize gated content, but not under a "membership" model.  Any solutions? 

Same. I also want to utilize gated content, but not under a "membership" model. In particular, I would like to change "Purchase Membership", at site checkout, to "Buy Now". 🤞