When you’re writing content for websites or services it should be as easy to understand as possible.
There is official guidance on writing for GOV.UK and writing for user interfaces, this covers a lot of the best practice to get your content simple and easy to understand, which in turn makes it more accessible.
In digital services, a lot of the time we are just asking users a series of carefully worded questions to guide them through what is often a complex process. There is guidance on designing good questions in the GOV.UK Service Manual.
For more in-depth accessibility considerations when writing content you should read the Content Designer guidance.