For one reason or another, some Muslims have not offered their daily salah. It could be that they didn’t pray all five prayers each day, or they completely abandoned it for a year or many years.
Some scholars say that once we are required to pray, either when we reach maturity or accept Islam, we owe each prayer we missed and we must make up every single one. How can a person begin to calculate or perform that? Well, they can offer extra prayers after their obligatory prayers.
But what if that puts them off prayer altogether and they just quit?
The other scholarly opinion is that you don’t have to repeat everything you have missed. You must make a good tawbah/repentance and promise never to leave salah again. In addition, you can pray as many other nafl/extra prayers as you are able.
May Allah make it easy for us and forgive us our shortcomings. Ameen.