To determine your 401K balance, allocation, and contribution history, you should first contact your Human Resources Department. They will most likely direct you to an online portal for your Plan Sponsor. If you have not accessed this information before, you may need to register for this access. Upon receiving a log-in and Password, you should be able to track your 401K information as often as you like.
Check with your plan provider. Generally you receive online access. What company is the manager of your 401k plan?