WhatsApp groups can be an effective tool for developing a loyal customer base for your business. Here are some steps you can take to use WhatsApp groups to build customer loyalty:

Create a WhatsApp group for your customers. This can be a private group where only invited members can join and participate.

Invite your customers to join the group. This can be done through email, social media, or other marketing channels.

Engage with group members regularly. This can include sharing updates about your products and services, answering questions, and providing helpful information.

Offer exclusive deals and promotions to group members. This can include special discounts, early access to new products, and other perks that are only available to group members.

Encourage group members to share their experiences with your products and services. This can include asking for feedback, reviews, and referrals, and responding to any concerns or issues that are raised. 

Encourage referrals among group members. Every time they make a sale, encourage them to invite a new customer to join the group.

By using these strategies, you can develop a loyal customer base through WhatsApp groups. This can help to build trust and credibility with your customers, as well as create a community of loyal supporters who are more likely to make repeat purchases and recommend your business to others.