Gauges
An important consideration when choosing strings is the gauge, this determines the thickness of the strings on your guitar and different gauges hold different key features.
Thinner strings are more commonly used for blues guitar as the thin strings cause a lot less tension. This allows more string bends and slinky licks. Thicker strings on the other hand are durable and are much less prone to breakage, making them ideal for heavy riffs.
Tonally speaking, thinner strings usually have a more bright, pronounced sound and thicker strings are warmer with much lower sonic response.
When deciding on a string gauge you’ll have to consider your playing style and the tone you’re trying to achieve. String gauges are measured by 1/1000th of an inch and commonly referred to by their high E string (9’s, 10’s, 11’s etc..) You can also get hybrid packs which will have heavier top strings for big, heavy power-chords and thinner strings for bends and solos.