Click on Share on your fundraiser page and choose WhatsApp. A ready-made message is waiting for you, in the tone you choose (personal, short or for a group). Feel free to adjust it: personal messages are read and forwarded more often. Then choose the contacts or group in WhatsApp. You can also post the message on your WhatsApp status.
Of course, you can also just copy-paste the link of your fundraiser page if you prefer.
Tip: Create a group or mailing list on WhatsApp. This way you can send the link to your fundraising page to several people at once.
With a group, everyone can see who is in the group. With a mailing list, people cannot see each other.