There are foundations for ageing skin, oily skin, acne prone skin, young skin, foundations with light reflecting particles, shimmer, firming gel and so many other types! Identify u're skin type first...if u have scars u'd need heavier coverage if u have flawless skin all u need is a tinted moisturiser..
I don't have blemishes, I use a concealer for my eyes...dot my foundation stick all over my face and blend with a slightly damp sponge.