Tithing in general sense simply means giving the ten percent. It seems that this principle of giving exist even before the Law of Moses since Abraham gave a tenth part to the king of Salem.
Heb 7:2 To whom also Abraham gave a tenth part of all; first being by interpretation King of righteousness, and after that also King of Salem, which is, King of peace;
When it comes to tithing in the Law of Moses, it is a system of taxation and an offering to God that benefits mainly the Levitical tribe since they didn’t receive a land inheritance.
Numbers 18:26 Thus speak unto the Levites, and say unto them, When ye take of the children of Israel the tithes which I have given you from them for your inheritance, then ye shall offer up an heave offering of it for the LORD, even a tenth part of the tithe.
Christians today though are no longer under this law since we no longer live under the law of Moses and most Christians are not Jews in the first place.
However, Christians are still commanded to give every first day of the week.
1 Corinthians 16:1 Now concerning the collection for the saints, as I have given order to the churches of Galatia, even so do ye.
1 Corinthians 16:2 Upon the first day of the week let every one of you lay by him in store, as God hath prospered him, that there be no gatherings when I come.
Here, we can see that we have to give as God has prospered us.
Although the exact percentage was not given, I believe 10 percent is a good start. However, if possible, we shouldn’t stop there. If we can give more then it would be better to give more so that we can exceed the righteousness of scribes and pharisees.
Matthew 5:20 For I say unto you, That except your righteousness shall exceed the righteousness of the scribes and Pharisees, ye shall in no case enter into the kingdom of heaven.