Not all reformers use TULIP.
It is my understanding that only Calvinists use TULIP.
I don’t think Lutherans, Armenians, and most Baptists subscribe to TULIP, although I have seen plenty of 3-4 point Calvinists in Baptists.
The term “Reformed tradition” typically only refers to churches which were influenced by the reformation movement which took place in Switzerland. The Lutherans, Baptists and Methodists would not, for example, be properly referred to as Reformed, although some Baptists do hold to Reformed theology. The Church of England has had a weird history with the Reformed, and the 39 Articles of Faith show quite a bit of Reformed influence, but I don’t think I’d lump them in with the Reformed either.
For the OP: TULIP is basically puts the teachings of Calvinism into a nice convenient acronym. TULIP in a nutshell goes something like this (people in the reformed tradition who post here can probably explain it better):
Total Depravity: man, as a consequence of the fall, is unable to choose to follow God without God’s prevenient grace (meaning simply grace which comes before human action) and election.
Unconditional Election: God has chosen the elect unconditionally for His own purposes. This is in contrast to the idea of Conditional Election, taught by Arminius, whereby God elects those for salvation those who he foreknows will have faith in Christ.
Limited Atonement: Jesus’ atonement was definite in its purpose. As a consequence, the atonement is “limited” to or only efficacious for those whom God has elected.
Irresistible Grace: God’s grace is completely efficacious. As a result, those who have been elected will be unable to resist God’s grace, but instead will be compelled into faith and salvation.
Perseverance of the Saints: Because God’s grace is efficacious, those who are of the elect will persevere unto the end. Those who leave the faith were never of the elect in the first place.