The method is very simple and depends on a cool android app that will let your to save any of contact in your android device when you are on a call. You will just need on the icon that will appear in your call screen to save the number. So proceed with the below steps.
Features Of Call Writer Android App
Enable speaker mode in your android when you click on icon.
Saved Notes will automatically get saved when call is ended.
Either you can use notepad or paint in it.
Multi designs notes saving option.
Steps To Setup App To Save a Number During a Phone Call on Your Android:
1.First of all in your android device download and install a cool app that is Call Writer
2.Open the app after installing and you will see screen like below.
3.Now tap on three lined sign button and in settings you can customize according to your wish.
4.Now whenever you make any call or receive any then you will see a dialer like blue icon. Just you have to tap on it and save anything that you want to save.
5.The written note will get automatic save when call ends up.
Thats it you are done, now there will be no need of any paper and pen, just a app is enough to save your things on ongoing calls.
So use the method and get up from the tension to find out pen and paper to note down important things on ongoing calls.