In Sweden, with indelningsverket (the allotment system) several farmers banded together in a rote and provided one soldier and his equipment, a croft for him and his family to live on and in return were free from tax.

The soldier would usually be one of the younger sons of one of the farmers or a crofter to one of the farmers. Becoming a soldier usually meant an increase in status - your own croft, the ability to support a family and being the man in the village that travelled (for exercises, which could be large festive events with markets etc around them), so there were usually not a lack of candidates for the position.

In war, the regiment the soldier belonged to would often need to raise a tremänning regiment (a dual one to either replace casualties or expand the army). Soldiers would then be conscripted from the farmers and crofters and their sons. Farmers as part of rote were extempt and usually their oldest sons were as well.

The priest kept records of births, migrations, marriages and deaths. The regiment kept records on the physical status of soldiers and the elder of the village or the local landshövding (governor) would choose which ones were to be conscripted.

Well, other than voluntary enlistments, some nations used mercenaries from the numerous German states. A good example of these mercenaries are the Hessians, which were even hired by the British during the Revolutionary war.

Depends on the nation. In England (Britain, UK, something?) you would sign up to fight, officers got their ranks by purchasing them (which meant many if not all officers were nobles since only nobles had the money). However Soldiers had to bring their own weapons and armour most of the time (which changed with the industrial revolution later since uniforms could be manufactured extremely quickly).

The navy was very similar with some differences i.e. press gangs which would roam the docks and forcibly conscript sailors to service on ships (particularly if you were American which back then was a very nebulous term).