The first time they click the link, it asks them to set up payments using their own banking info. I NEVER SEE THEIR PERSONAL BANKING INFO.
One they have set up their own info, when they click the link on subsequent invoices, they log-in to the Intuit system USING INFORMATION THAT I NEVER SEE.
I did a test run before using it, billing myself $1.00 and and paying myself $1.00. ONE DOLLAR was deducted from my personal checking account and FIFTY CENTS was deposited into the Landscape Checking account. The balance of 50 CENTS I wrote to "bank fees" expense, so the $1.00 invoice I was carrying on QB cleared.
Now, as to your question of HOW MUCH they can pay -- good question
Tonight or tomorrow, I'll re-bill myself and let ya know - LOL!
You know when YOUR CHECKING ACCOUNT has received the money, because you receive an EMAIL letting you know that so-and so has paid you online. The email arrived from Intuit. "IF" you do online banking and download the banking info into your QB, you then would process the payment the usual way. It's just that YOU did not actually make the deposit.
Are you a QB user? If so, I use 2012 -- self-taught. Look-up their tutorial on receiving payments.
I'll BBL or tomorrow w/info on the partial payment etc.
Hope this helps a bit.