Yes, the website is legal and legit. Codashop is the official partner of Activision and Call of Duty: Mobile, which means it is a trusted and authorized platform for making in-game purchases and transactions. Using COD:M store to buy in-game currency, items, or content is a secure and legitimate way to enhance your gaming experience in Call of Duty: Mobile. You can have confidence that your transactions on the website are backed by the official partnership and the necessary approvals, ensuring a safe and authentic gaming experience.
Please check out the official announcement about this partnership:
Activision opens its first Call of Duty: Mobile web store with Coda
COD:M FB Page Official Store Announcement