Hi there, PureClean.
Welcome to the QuickBooks Community. I'll be sharing some information on how sending an invoice or payment to a customer works in QuickBooks Online.
Currently, there's no option to directly text a payment link from your phone. Meanwhile, QuickBooks offers a user-friendly method for sending invoices to your customers. You can open your QBO through a browser and open the said transaction. Then, copy the link of the entry and send it via SMS to your customer so they can view their invoice from there.
Here's how:
On the other hand, I encourage you to submit a request about texting a payment link for an invoice via phone. Please click this link so you'll be routed to the Customer Feedback page for QuickBooks Online. From there, you can enter or search your request so you're able to see if there are other users who want to add the feature the same as yours. Then, be able to vote for this option so will be available in the future asap.
Please refer to this article to view detailed steps on how to record single or partial payment for an invoice: Record invoice payments in QuickBooks Online.
If there's anything else you need assistance with sending invoices or payment links, let me know in your reply. I'm just a few clicks away from you.