Need some clarification

Hi,

I am just starting to learn Japanese and if I want to say "Please send me (thing)"...

I should say ...を送ってください?
Does this works with generally everything that can be physically given (ie. paper, money, food, letters, etc)? If I want to please send me an email can I still use
私にメールを送ってください?

Sometimes I see "...をお伝えください" and "...を教えてください"

Do they have different meanings in context?

Are there any special cases that I need to take note?

…を送ってください yes, your understanding is correct.

...を教えて下さい。 means "please tell me (something)," like if you were trying to find out shipping charges from an online shop in Japan to yourself (for example) in the US, you would ask "アメリカへの 送料を 教えて下さい。"

...をお伝え下さい。does not mean the same thing as above. If it was used in the same way, it was a mistake. If you notice the お in お伝え, that is an honorific, so you would not ask the other person to "respectfully tell me something."
...を　お伝え下さい would be appropriate if you want to ask that person to convey something (respectfully) to another person.
Ａさんに　私からの　お礼を　お伝え下さい。(Please convey my words of gratitude to Mr./Ms. A.)

送ってください - yes, it is right.

お伝えください - leave me message, or, tell my regards to , or something like this.