Do you mean 'what is the purpose of SUVAT equations?' ??
SUVAT equations are 'shortcuts' to relating displacement, velocity, acceleration, and time of an object together in the strict case where acceleration is constant (uniform) for that object.
Remembering them helps you answer mechanics related questions in the context of motion where forces are not directly considered (this is called kinematics).
E.g. a problem may be posed whereby (very often) you have to identify what is given to you (s, u, v, a, or t) and decide what you need to determine, and then think about which SUVAT equation(s) help you do that, and then use them carefully within the context.
One common context is projectile motion because objects under the influence of gravity are treated to have a constant acceleration of approx. 9.8 m/s^2 towards the ground, so you can expect to use SUVAT a lot in these types of contexts.
I don't know what stage of your A-Level you are at, but in Year 2 you learn that in the case of non-constant acceleration we see that displacement, velocity, and acceleration are all related via the more powerful and general tool of calculus ... and it just so happens that if you treat acceleration as a constant in this scope then SUVAT equations fall out of calculus as a consequence.