Please read our guide on how to install your email signatures in the Gmail App on iOS 7, 8 and 9 on iPhones and iPads.
Please note: if your email signature doesn't install into your Gmail desktop web client, because you receive the "email signature is too long message" and you are using our browser extension to insert your email signatures, you won't be able to use your email signature in the Gmail App.
To use the signature in the Gmail app, you need to make it smaller so that it will paste directly into Gmail's settings on your Gmail desktop web client and not use our browser extension.
Use our handy "Count Characters" button on the right hand side (red menu), while editing your email signatures to see if they will fit in Gmail, while you are creating them. They need to be under 10,000 characters.