Can the payer type any amount to charge?

The Payment block charges the fixed amount you set. A number field can store what they say is due. It does not change the Stripe charge.

Can I send a quote, then a pay link?

Yes. Use one form for the quote request. Use a second form as the pay link. There is no built-in quote-to-invoice pipeline.

Tool

Invoice and quote forms

People search for an invoice generator when they want a bill they can send and get paid. Request Forms can host a pay link with a Stripe charge and a stored invoice number. It can also collect a quote request. It does not number invoices, post to a ledger, or print a tax invoice PDF.

The job

Collect payment against an invoice, or take a quote request.

What Request Forms can do

A Payment block for a fixed deposit or fee.
Short answers for invoice number, PO, and company.
A calculated field for a line total after submit, such as quantity times unit price.
A hidden field that reads an invoice id from the URL.
File upload if the payer should attach a PDF.

What it cannot do

No invoice numbering, tax engine, or accounting export.
No generated PDF invoice as the product.
The Payment block charges the amount you set. It does not read a typed amount as the charge.
This is not QuickBooks, Stripe Invoicing, or an AR system.

How to build it

For a pay link, add Invoice number, Amount due, and a Payment block.
Add a hidden field if you pass the invoice id in the URL.
For a quote request, collect scope, dates, and a file. Skip the charge, or take a deposit.
Connect Stripe on the organization, then publish the form.

When to pick each

Pick Request Forms

You want a hosted pay-this-invoice page with a fixed Stripe charge.
You want a quote request form that lands in the same inbox as your other forms.

Pick another product

You need invoice numbering, tax, and a ledger. Use accounting software.
You need Stripe Invoicing or a PDF bill as the main artifact.

Questions

Can the payer type any amount to charge?: The Payment block charges the fixed amount you set. A number field can store what they say is due. It does not change the Stripe charge.
Can I send a quote, then a pay link?: Yes. Use one form for the quote request. Use a second form as the pay link. There is no built-in quote-to-invoice pipeline.