There is no such software, tool, or app which will offer you the direct translation. You have to do it on your own or ask an expert to do it for you.
If you know the Sanskrit language and you want to translate English to Sanskrit then you need to know the vocabulary first. You can use the English-Sanskrit dictionary for that. The second very important thing is sentence formation or grammar. You must know grammar well. You need to know nouns, pronouns, and verbs - at least learning these three things will make your work easier.
