Say : Thanks a lot for your help ! or Thank you so much I'm really thankful ......

To avoid future mistakes, if you put the sentence or phrase in quotation marks (" ") it'll be more clear. "She has been asking about it since morning and demanding it to be sent." Is grammatically correct. If you're speaking this sentence out loud, it's allowed to drop the "to" in "it to be sent" (demanding it be sent"). But, in writing, it's best to leave that in. There might need to be a comma(,) in between "morning" and "and" to tell the reader to pause shortly ("morning, and demanding") Hope this helps.

Sorry was absent minded when writing that question I meant thank you very much for your help The question was about the following sentence, She has been asking about it since morning and demanding it to be sent.