How can I restore my iPhone data after doing reset?

Did you make backups of your phone before you reset it? If so, restore your data from there. If you didn't make a backup, your data is gone.

Restore your IPhone from a backup -

Restore your iPhone, iPad, or iPod touch from a backup - Apple Support

When you go through the setup process after completely erasing the device, you'll be given the choice to restore from an iCloud backup or a backup from your computer.

Choose the appropriate option and restore.

If you did not have a backup at all, the best you can do is sign into your iCloud account and sync the data that was stored there down to your phone.