The 144,000 are sealed in their foreheads BEFORE the False Prophet is allowed to enforce the Mark of the Beast (Revelation 7:4)
AFTER the sealing of the 144,000, the False Prophet (the 2nd beast) forces EVERYONE ELSE ("ALL") to receive the mark of the Beast (Revelation 13:16).
Of course the 144,000 sealed by God in their heads will refuse, and they will be beheaded. The 2 witnesses also refuse and they too are killed (Revelation 11:7).
So everyone will either be Marked or Killed. Everyone who is Marked will be killed with the Sword coming from Jesus' mouth when He returns on the white horse (Revelation 19:21). Only those who were beheaded will be resurrected in the "First Resurrection" and they will rule with Christ on earth for 1,000 years. The rest of the dead do not come back to life until the 1,000 years are ended (Revelation 20:5)
And the false prophet kills the two witnesses.
No, he does not force everyone else take the mark. If he did no one.
People are forced to take the mark to be able to buy and sell.
If they don't take it they can't do either.
Revelation 19:20 New International Version (NIV)
20 But the beast was captured, and with it the false prophet who had performed the signs on its behalf. With these signs he had deluded those who had received the mark of the beast and worshiped its image. The two of them were thrown alive into the fiery lake of burning sulfur.
16 It also forced all people, great and small, rich and poor, free and slave, to receive a mark on their right hands or on their foreheads, 17 so that they could not buy or sell unless they had the mark, which is the name of the beast or the number of its name.