One extra point is awarded.
When you score a touchdown in American football, Six points are awarded. You then have the choice to either kick the ball ball through the goalposts for one extra point, or run another play for two extra points.
Three points are awarded for a field goal in American football.
Points are not given for a Touchback. I believe you are confusing this with a Safety, where two points are awarded to the defense.
There would be many answers to this question as there are many football codes. American football, Gaelic, Aussie rules, Rugby League, Rugby Union etc. However if you mean the most popular form of football in the world, Association Football (Soccer) there are no points awarded for goals. Points are awarded for winning (3) or drawing (1).
AFL awards teams two points each in a draw, which is half of the regular points awarded for a victory.
6 A touch-down is worth 6 points with out the extra conversion points
3 points for a field goal and 1 point for an extra point.
In the CFL, a rouge is worth 1 point and is the equivalent of a touchback in the NFL. No points are awarded for an NFL touchback.