Using the free T&Cs

You can either:

HTML code that you can cut-and-paste into your website for these purposes is set out below.

User agreement (link):

<a href="https://www.website-contracts.co.uk/user-agreement.html">User agreement</a>

User agreement (iframe):

<iframe src="/user-agreement.html"; style="border:none"height:200px;width:300px;">User Agreement</iframe>

Customer agreement (link):

<a href="https://www.website-contracts.co.uk/customer-agreement.html">User agreement</a>

For the customer agreement (iframe):

<iframe src="https://www.website-contracts.co.uk/customer-agreement.html" style="border:none"height:200px;width:300px;"></iframe>

You do not need to (and indeed cannot) edit the free T&Cs, although you will need to:

ensure the documents are linked to, or embedded, in an appropriate way on your website;
add a legal information page to your website setting out website-specific information (e.g. a company name and registration number);
provide supplemental terms and conditions for any features or functions that are not appropriately covered by the free T&Cs.