I am designing something like a wallet where users can withdraw from it. I'd like to give users the option to withdraw any amount, however, I do not know how to let my users know in a really obvious way that the amount can be edited. Currently, I'm deciding to put a text saying 'click here for desired amount' and connecting it via an arrow to the bottom $300.70 for users to know.

Please share with me your thoughts and opinions. Greatly appreciated!
If you do not understand where I am coming from, do leave a comment as well! Thank you :)

[![enter image description here](https://i.stack.imgur.com/SUCVR.jpg)](https://i.stack.imgur.com/SUCVR.jpg)

Update: Thank you everyone for giving me so many constructive feedback! I really appreciate you guys taking your time out! And after posting, I came up with a high fidelity mockup! But after reading everyone's comments, I'm going to think about it again!

[![enter image description here](https://i.stack.imgur.com/hQxls.png)](https://i.stack.imgur.com/hQxls.png)