Yes, WhatsApp users can see your phone number if you have it linked to your WhatsApp account. When you sign up for WhatsApp, you need to verify your phone number, which becomes your unique identifier on the platform. This phone number is visible to other WhatsApp users in various situations:

1. In Contacts: If someone has your phone number saved in their phone's contact list and you have WhatsApp, they will automatically see your profile in their WhatsApp contacts, including your profile picture, status, and the name you've associated with your phone number.

2. Group Chats:  When you join a WhatsApp group, all other members of that group can see your phone number if it's not hidden in your privacy settings. Group members can often view the numbers of other participants, especially in smaller groups.

3. Individual Chats: In one-on-one chats, your phone number is typically visible to the person you're chatting with, unless you've specifically set your privacy settings to hide it.

4. WhatsApp Business: If you use WhatsApp Business, your phone number may also be visible to customers or clients who interact with your business account.

WhatsApp takes privacy seriously and offers various privacy settings that allow you to control who can see your profile information and phone number. You can adjust these settings to limit the visibility of your phone number to only specific contacts or hide it altogether from non-contacts.

To modify your privacy settings on WhatsApp:

1. Open WhatsApp. 

2. Go to "Settings." 

3. Select "Account" and then "Privacy."

4. You can then adjust who can see your profile photo, status, last seen, and about, as well as who can add you to groups.

By managing your privacy settings, you can have more control over who can access your phone number and other personal information on WhatsApp.