FTP is File Transfer Protocal, and should be information you can get
from your Web Hosting service. There is a Username, and a Password.
Either your webmaster will have this information or the company
hosting your websites will have it. You may have gotten this
information when you setup the account with them, so you might want to
check some early emails.
PayPal ( www.paypal.com ) is an online payment system. The company you
are working with should have sent you a link via email, or have a
button on their website, that you can use to get their account name.
You can then go to the PayPal website, by clicking on that emailed
link or web page button,... fill out the Pay Pal form, enter credit
card information and pay them.
Now, something I want to add here as a personal note. Adding content
to a blog program doesn't normally take FTP information. That should
not be required. So before going any further with this company, check
them out. Get some references from them and have them explain to you
why they need the FTP information.