How to add or delete words that are saved in my texts

When I'm texting some words are saved that I want to delete and I would like to add some words

Strange words are auto added to your dictionary, if you want to get rid of one, long press on the word when it gets suggested, then you should get the option like "do not suggest this word again" or similar. Not knowing your device or software or keyboard, this is generic advice, but it should be close... Happy days!