Please find the instructions below.
Open the Speechify app
Go to your Speechify library and open the document you wish to read
On the reading screen, next to the kebab (three-dots) icon, tap the reader mode icon as pointed out in the screenshot below
Original mode (screenshot 1) displays the original view and contents of the imported document, whereas reader mode (screenshot 2) contains the text only for greater visibility and better comprehension.
Hit the Aa icon to change the reading appearance based on your preferences.