Free version works great if you don't mind an occasional ad on the phone itself (not in the content on screen). Otherwise, one time purchase of 3 or 4 dollars).
The above is how I cast wirelessly with my Android. There are other casting apps available, but I have found this works best for me. You may want to search for a few in your phone's app store and see if you prefer another.
Roku Community Streaming Expert Just another Roku user... I am not a Roku employee. Insignia RokuTV, Ultra 4660, Premiere+ 3921, Express 4k+ 3941, Streambar 9102