I always write down important information such as: user name and password, bank account... to the text apps on phone (Ex. Note app on iPhone...) to avoid forget them and easy to check for verifying them. If the phone has no passcode and I lose it, so what is happened on my secret information?
I still encourage you to use the Text App to store your personal information but you should not write them completely.
Example: exact User Name: Jonh
Password: redwood@
On your phone in Note app you should write:
Jonh
redwood
Note: you have to omit "@" but you need to remember one or more special characters in your mind (in this example "@") and always remember that they are written before or after the password when you type them. OK, let stop talking about that.
I will show you how to hide text in your selected images using CMD promt and Notepad on windows platform. This way is more security than method above to hide your information.
- Select a photo file. Ex. abc.jpg
- Store it on drive C: or D: because it is easy to access by using CMD promp. I suppose you store on drive D:\abc.jpg
- Open command promt by pressing Key Windows + R then type: cmd -> Enter.
- For easy to access your photo, you should change directory to drive D: in command promp type: cd /d d: then press Enter
- You are standing on drive D: now writing your information to the photo by type: echo "Enter your personal info here, Ex: User Name: Jonh Password: redwood@" >> "abc.jpg" press Enter. Note! you can omit double quote " in echo command. Ex: echo Enter Ur...

The image show command from 4 to 5.
- Open Notepad -> in file type choose All files then brows your file to open-> scroll down to the end of line you will see your information. Note: Don't save Notepad! The photo file will be broken.

The information in Notepad.