You’ve basically got two options. You can use contactless PAYG, which will cap at the price of a weekly travelcard in any Monday to Sunday week. Or if you want to commit to a monthly or longer season ticket, you can get a Henley to zones 1-6 travelcard. This can be used either way round, but the outboundary station must be used as the origin.
There are two prices for season tickets from Henley; direct or via Reading. The via Reading option is significantly more expensive, but allows you to use fast trains from Paddington to Reading then heading back to Twyford.
If you use contactless, you can circulate via Reading without paying extra as long as you don’t leave the paid area at Reading.