There are many different wallets on your app store to choose from, the wallet acts as a client to use the Bitcoin network and will transact with any other Bitcoin wallet just like when you send an email it doesn’t matter who the other persons email provider is.
Once you have downloaded a wallet app, open it and choose create new wallet.
The app should now prompt you to write down a ‘master seed’.
The master seed is a list of words, usually 12 words, which are cryptographically linked. Write these words down carefully in the correct order and keep safe as the master seed is required if you need to restore your wallet.
If you lose your device and don’t have your master seed you will be unable to access your wallet and all funds will be lost forever!
The wallet should ask you to confirm the words you have written down before continuing.
If the wallet you download doesn’t require you to make a master seed it means you are not in control of your private keys, and not actually holding your Bitcoin on your device, instead you a trusting a third party to hold the private keys for you. These type of wallets are less secure.