You're confusing two different concepts here.
You have shielding, which is part of energy work.
Then you have protection magic, which is done through spells, rituals, etc...
A spell does not create a "force field" as you're asking for however you can use it to create abstract boundaries if you will to protect yourself from the effects of other spells.
Then you have actual shielding, which is closer to what you might refer to as a "force field", it's more concrete and normally can be put up immediately no need to wait for the effects of the spell you cast. A shield is done through surrounding yourself in charged psi programmed to protect you from something, it can be programmed to protect against spells.
Either one works, but I'd say protection magic or spells as you asked for is for long term protection and shields are in the moment, temporary need.