Assuming you're new to the Souls-style levelling system, I would recommend starting out with a quality build. In other words, invest in Strength and Dexterity in equal measure. These kinds of builds are popular amongst beginners because it allows you to use pretty much every weapon in Elden Ring, aside from any Arcane or Intelligence ones. You can respec in Elden Ring, so don't be afraid to try out different weapons and styles. Once you find one you like, you can redistribute your stats around that particular weapon type and scaling.