You are allowed by law, to complete the immigration forms yourself. You are not required to be represented by a lawyer to fill out your immigration forms. There are laws that apply if a non-lawyer and non-authorized agent or notario begins to fill out the immigration forms for others.
However, filling out the forms oneself may not be a wise approach! An experienced immigration lawyer can review and spot issues that you would not be able to catch. Therefore, it depends on your situation and your evidence if you would be able to accurately and completely fill out and file the forms yourself. If you have any "history," with immigration, criminal, or other issues, that alone should provide you with what we call "the little voice" to know you need at least a review of what you would plan to file. Another answer would be... the short way may be the long way!
If you cannot afford a lawyer, there are legal clinics at law schools and pro bono clinics where you may be able to find assistance. Some of these may be listed on the USCIS web site.
Well, you can put on a pair of skis, but without lessons, you might crash, injure or even kill yourself.
some who do not qualify for immigration or a non-immigrant work visa may be referred to immigration court for deportation in some circumstances. There are risks to igoring the immigration and visa laws. There are also risks when filing for a visa petition for which you may not qualify.
The immigration petition procedure is a legal process. This means that seeking legal advice just to decide whether to prepare the forms and spend the money to file the applications makes sense. If you are unsuccessful or accidentally violate the law, then you can be barred from successfully filing for a visa. In some cases, the immigration bar can last a lifetime.
Most attorneys charge less for an appointment or teleconference than the cost to file an immigration petition with the USCIS. For that reason, it makes sense to ask and answer some questions, so that a candid and experienced immigration attorney can make sure that you don't make a mistake. In some situation, an attorney may recommend against filing or provide you with enough information to help you decide what is in your best interest.
The above is general information and does not create an attorney client relationship.