Hi @SaraW1987 ,
It can still be sent as HTML so on the end
"To upload your document open the app: <a href='" &
<PowerApps Url> &
"' > here </a> find your board slot . . . "
Note the single quotes inside the doubles. HTML interprets both the same and the URL need to be enclosed in quotes. PowerApps Concatenate will strip the doubles, so you are sending
To upload your document open the app: <a href='https:apps.powerapps.com/play/ . . .' > here </a>
find your board slot . . .
to the email, which should render a hyperlink under the word "here"
If this post helps, then please consider Accept it as the solution to help the other members find it more. It also closes the item.