You are eligible to file this form if you are a US citizen or lawful permanent resident. The purpose of Form I-130, Petition for Alien Relative, is to help your foreign family members receive permanent resident status and immigrate to the United States.
However, submitting Form I-130 is only the first step in helping your alien relatives immigrate to the US. An eligible family member must wait until there is a visa number available before he/she can apply to become a lawful permanent resident.
This process is called family-based immigration. And it can take from few months to several years, depending on the country of origin, your type of relationship and your status (citizen or permanent resident).
When you file Form I-130 your relative gets a place in line for a visa number, and that place is based on the filing date of your petition, so the sooner you submit the duly executed Form I-130 the sooner your relative will get a green card.