Your message is mostly clear, but it could use some minor adjustments for better clarity and formality. Here’s a revised version:
"I got your number from Donath. Could you please add me to the WhatsApp group (BESAG)? I would also like to join the EHASE NGO. Below are my identification ID, phone number, and email:"
Feel free to fill in your identification ID, phone number, and email after that last sentence.