Is a lawyer or immigration agent required to fill a Express Entry application?
Can I apply by myself?
Is there any difference in scoring or evaluation between an application self-submitted and one made by a lawyer?
No, you don't need to have a lawyer or immigration agent help you fill out a Canadian Express Entry application. You can definitely apply on your own. There will be no difference in scoring or evaluation between a self-submitted or immigration-agent-submitted application.
However, if you feel uncomfortable or confused by the application instructions, you might engage an agent to help you understand the instructions and to make sure you have all the paperwork compiled properly.