Please! How do I form a negative sentence like: "Don't sent them to me." Thank you very much.

The negation "ne...pas" brackets the reflexive indirect object "me", the direct object "les" and the verb "envoyez".

-- Chris (not a native speaker).

Dear Chris, WOW! Thank you very much for your extremely quick answer. I truly appreciate it!!! Yes, you must be a very positive speaker!!! However, we don't use any stress pronouns for the sentence like that? For example, when we say, "Send it to me"-->"Envoie-le-moi." Is this incorrect? That is the reason why I could not figure out how to make an impératif in negative form. Thank you, again!! umi

You use stress pronouns when it follows a preposition or comes at the end of the sentence. Neither is the case here, hence no stress pronoun. Greetings, -- Chris.

Bonjour Umi et bonjour Chris !

To complete Chris's great answer, here is a link to our lessons on negative imperatives:

https://kwiziq.learnfrenchwithalexa.com/revision/grammar/how-to-form-simple-negative-commands-imperatif

https://kwiziq.learnfrenchwithalexa.com/revision/grammar/how-object-and-stress-pronouns-behave-in-negative-commands-imperatif

Bonne journée !

Bonjour Aurélie et Chris, Merci beaucoup pour vos explications !! Cordialement, umi