Cake Wallet allows you to save send and exchange templates. These can be saved as either a fixed amount of cryptocurrency (eg: 1.234 XMR) or a fixed equivalent amount in fiat currency (eg: 123.45 USD).
You can use templates for your most common transactions. You can create templates using a set cryptocurrency amount (eg: 1.23 XMR), or an approximate fiat amount (eg: $123.45).