I want to change the default paper size from letter to A4.

[Hellboy1982]

How to change default paper size to A4. Or how to make My preset the default one. 

It is annoying that all the time I have manually select the right size, and lost a lot of ink and paper 

This was not the case before my subscription comes alive. My printer is used by family and they used to just print not selecting paper sizes . I assume this is a bug in your program

[Max3Aj]

@Hellboy1982, Welcome to HP Support Community. 

Thank you for posting your query, I will be glad to help you. 
It sounds like your HP DeskJet 2820e is defaulting to an incorrect paper size, likely due to HP Smart settings or Windows printer defaults. Since this issue started after activating your subscription, it may be related to Instant Ink settings. Here are steps to set A4 as the default paper size:

Steps to Set A4 as Default Paper Size:

Change Paper Size in Windows Printer Settings

1. Open Control Panel and search for Printers & Scanners.
2. Select your HP DeskJet 2820e and click Manage.
3. Click Printing Preferences.
4. Under Paper/Quality or Advanced, look for Paper Size and select A4.
5. Click Apply and OK.

Update Paper Size in HP Smart App

1. Open HP Smart.
2. Go to Printer Settings.
3. Locate Preferences or Paper Handling.
4. Set the default paper size to A4.

Set Your Preset as Default

1. Open Printers & Scanners as in Step 1.
2. Click Manage → Printing Preferences.
3. Under Presets, select your custom settings and Save as Default.

Check Instant Ink/HP Account Settings

Since the issue started after Instant Ink activation, try:

1. Sign in to your HP Smart Account (Instant Ink).
2. Navigate to Your Printer → Settings.
3. Check for any paper size settings or auto-adjustments.

Reset Printer Defaults

If the above steps don't work:

1. Factory reset the printer from its settings menu.
2. Reconnect it and reconfigure paper size settings.

By following these steps, you should be able to set A4 as the default paper size and resolve any printing issues. 
 

I hope this helps. 

Take care and have a good day. 

Please click “Accepted Solution” if you feel my post solved your issue, it will help others find the solution. Click the “Kudos/Thumbs Up" on the bottom right to say “Thanks” for helping! 

Max3Aj

HP Support