No you can't apply for all the posts in SSC CGL exam.
You can apply for only those post that match with the eligibility criteria. The post for which you don't meet with the eligibility criteria, you can't apply for the same.
For more information you can refer to the link given below -
Hope it helps :)
SSC CGL Tier I Mock Test Series
Start preparing for SSC CGL Tier I with S Chand Test Series