In most cases, the batteries in wireless earbuds are not designed to be user-replaceable. This is due to their compact design and the need for water-resistant sealing. Some manufacturers offer battery replacement services, but this can be costly and may not be worth it compared to buying a new pair.
A few brands are beginning to design earbuds with replaceable batteries, but this is not yet common in the industry. Always check your warranty and the manufacturer's policy before attempting any repairs.