You can for ecxample add a check on who can call the function like so: 

https://beta.solpg.io/tutorials/battle-coins

    const ADMIN_PUBKEY: Pubkey = pubkey!("REPLACE_WITH_YOUR_WALLET_PUBKEY");
    ...
    #[account(
        mut,
        address = ADMIN_PUBKEY
    )]
    pub admin: Signer<'info>,