When to make dua during prayer

Salam, i have just started praying and i am in the process of learning more about islam. While I know you can make dua during sujood, i was wondering if it is permissible to ask for worldly things like marriage/a specific person for marriage and whether it can be done in English. The second part of my question is related to duas before and after tasleem. Some say it can be done before tasleem, others say it can be done after tasleem. What is the proper way to do it as I want to make sure I do not make a mistake. (My questions relate to prayers done at home) Thank you