Do you mean “What to say to someone who has done tap” — as in Jain tapasya/fasting?

You can say respectfully:

• “Tap ni khub khub anumodana.”
• “Aapna tap ni anumodana.”
• “Aapnu tap safal thay.”
• “Aapne uttam bhav thi tap karyu, eni anumodana.”

In English, you can say:

• “Anumodana for your tap.”
• “I sincerely appreciate and rejoice in your tapasya.”
• “May your tap help in spiritual purification.”

The most traditional Jain expression is:

“Tap ni anumodana.”

It means you are joyfully appreciating their spiritual effort without pride or attachment.