Ideally, a tenancy agreement is something you should be prepared to spend a few quid on. After all, it's likely that your rental property is one of your most valuable assets. You won't want to be stuck with a dodgy tenant due to the fact you've downloaded a poorly-constructed agreement from the Internet. But if money's a little tight, you may feel you have no other option but to down the free route. If you do so, make sure your agreement includes everything you want covered before asking your tenant to sign it.
Navigate to free tenancy agreement pages on sites such as Rentify, LawDepot.co.uk or Pims.co.uk. You'll typically have to sign up for an account with any sites you use to create a rental document, so may have to put up with marketing emails once you've done so. Some free tenancy agreements will come in PDF form emblazoned with the logo of the website you used to create them, which may not inspire much confidence in your tenant.
Complete the free tenancy agreement creation process, preferably on as many sites as possible. Some services will merely ask for your name, while others will collect more detailed information to help them tailor your document to your and your tenant's circumstances. You may decide that the latter will be the better option. As everything you're creating is free of charge, you'll have nothing to lose but your time by downloading as many free tenancy agreements for review as possible.
Read through all the documents you've created thoroughly. This may take some time, but it's vital to you make sure you have all bases covered. Once you've found an agreement that's as close to what you're looking for as possible, add any clauses you'd like included that are missing. If your chosen agreement is in an uneditable format such as a PDF, cut and paste copy to a word processing document.
Ask somebody with experience in property law to take a glance over your contract. If you're not on friendly terms with a person equipped with the requisite knowledge, consider paying a property solicitor to have a quick read through. This will be cheaper than having a professional draw up a contract from scratch, and could highlight a glaring problem with your agreement that has the potential to cause you serious problems down the line.
Sign your contract in duplicate with your tenant in front of an independent witness. Have your tenant read through your document and initial each page to indicate that she has read and understood every clause. Your tenant should keep one signed copy of your agreement, while you should hold onto the other. Make a digital copy of your signed tenancy agreement and put the original in a safe place.
If you're not going to pay to have a tailored tenancy agreement drawn up, at the very least have your tenant's background professionally checked and referenced. Use companies such as HomeLet, Endsleigh or Experian.