Quote vs. estimate
An estimate is a guide price that can change. A quote is an offer to do stated work for a stated price. The customer's signature on your quote PDF is the acceptance.
Contractors often use the words quote and estimate as if they were the same. If the price then moves, that confusion is what ends up in a dispute.
Write the quote in the tool you already use. Export it as a PDF. Upload that file to ChickenSign, place the signature box, and send the private link. ChickenSign does not rewrite the quote.
What to put in the PDF before you upload it
Your quote PDF should state the scope of work, the price and VAT status, when you get paid, how variations are agreed, and any consumer cancellation notice the law requires.
Scope: the tasks, materials, and exclusions.
Price and VAT: whether the figure includes VAT, has VAT added, or has no VAT because you are not registered.
Payment: deposit, stage payments, and the balance.
Variations: extra work is agreed in writing, in a further PDF the customer signs, before you buy materials.
Consumers: if the Consumer Contracts Regulations 2013 apply, the cancellation notice belongs in your PDF. ChickenSign does not insert it.