What is the Level and Previous leve in Donation information

Hi @suneel kumar​ and welcome! NPSP Levels give you a way to track a constituent's level of commitment and engagement based on criteria such as total gifts or number of hours volunteered. These two fields capture the contact's current level and previous level, if they had one.

Here are some great resources as you're @Nonprofit Get Started Hub​ :

• Product Documentation: Create and Manage Levels
• NPSP How-To Series: Levels with Engagement Plans
• Trailhead: Engagement Plans and Levels in Nonprofit Success Pack
• Webinar: Get Started: Engagement Plans and Levels