You can add a description to the Start page (the page that constituents see first when they begin a process). Descriptions can provide useful context for why someone might want or need to complete that particular process.
To add a description:
Navigate to the Start page for the workflow you'd like to add the description to.
Click the Add description button beneath the Workflow title.
If the workflow already has a description you can edit this description from the Start page of the process if you're logged in to your admin account by clicking on Edit at the end of the description text area.