No, some spells however make attacks vs. touch AC. Touch AC is targets AC without armor.
Edit: Guns can make attacks against touch AC, within correct range. Also some special attacks make attacks vs. Touch AC rather than normal AC (Such as Weapon Master's Unstoppable Strike ability).
Can I make a touch attack anytime? Iam trying to strike someone in combat.
You can use your hair to deliver a held touch spell, just like any other natural attack. Most people would rule that this is not "striking" the foe, merely touching it, so it would not activate the free/swift combat maneuvers.
Were could I get information what striking means?
It's not a reserved game term, it's just a word.
World English Dictionary
strike (straɪk)
—vb (usually foll by with) (sometimes foll by out) , strikes, striking, struck, struck, stricken, struck, stricken
1. to deliver (a blow or stroke) to (a person)
2. to come or cause to come into sudden or violent contact (with)
3. (tr) to make an attack on
4. to produce (fire, sparks, etc) or (of fire, sparks, etc) to be produced by ignition
5. to cause (a match) to light by friction or (of a match) to be lighted
6. to press (the key of a piano, organ, etc) or to sound (a specific note) in this or a similar way
7. to indicate (a specific time) by the sound of a hammer striking a bell or by any other percussive sound
8. (of a venomous snake) to cause injury by biting
9. (tr) to affect or cause to affect deeply, suddenly, or radically, as if by dealing a blow: her appearance struck him as strange; I was struck on his art
10. to render incapable or nearly so: she was stricken with grief
11. (tr) to enter the mind of: it struck me that he had become very quiet
12. to render: I was struck dumb
13. (tr) to be perceived by; catch: the glint of metal struck his eye
14. to arrive at or come upon (something), esp suddenly or unexpectedly: to strike the path for home; to strike upon a solution
15. to set (out) or proceed, esp upon a new course: to strike for the coast
16. (tr; usually passive) to afflict with a disease, esp unexpectedly: he was struck with polio when he was six
17. (tr) to discover or come upon a source of (ore, petroleum, etc)
18. (tr) (of a plant) to produce or send down (a root or roots)
19. (tr) to take apart or pack up; break (esp in the phrase strike camp)
20. (tr) to take down or dismantle (a stage set, formwork, etc)
21. (tr) nautical
a. to lower or remove (a specified piece of gear)
b. to haul down or dip (a flag, sail, etc) in salute or in surrender
c. to lower (cargo, etc) into the hold of a ship
22. to attack (an objective) with the intention of causing damage to, seizing, or destroying it
23. to impale the hook in the mouth of (a fish) by suddenly tightening or jerking the line after the bait or fly has been taken
24. (tr) to form or impress (a coin, metal, etc) by or as if by stamping
25. to level (a surface) by use of a flat board
26. (tr) to assume or take up (an attitude, posture, etc)
27. (intr) (of workers in a factory, etc) to cease work collectively as a protest against working conditions, low pay, etc
28. (tr) to reach by agreement: to strike a bargain
29. (tr) See also special jury to form (a jury, esp a special jury) by cancelling certain names among those nominated for jury service until only the requisite number remains
30. (tr) rowing to make (a certain number of strokes) per minute: Oxford were striking 38
31. to make a stroke or kick in swimming
32. (tr) (in Malaysia) to win (a lottery or raffle)
33. strike home
a. to deliver an effective blow
b. to achieve the intended effect
34. strike it lucky, strike lucky to have some good luck
35. informal strike it rich
a. to discover an extensive deposit of a mineral, petroleum, etc
b. to have an unexpected financial success