When someone wants to directly help a family member gain legal status in the U.S., the first step is the filing of an I-130 petition. Residency, which is the legal status that green card holders have, can only be considered and approved after an I-130 has been approved.
The approval of an I-130 petitions means that the family relationship has been established and acknowledged by USCIS. For example, if you have petitioned a child, an approval means that USCIS has acknowledged that the person you filed for qualifies as your child under the law. The meaning of “child” can include not only biological children, but sometimes stepchildren and adopted minors.
If you have petitioned your spouse, an approval of your I-130 petition indicates that USCIS has both acknowledged that your marriage is legal and that your relationship is genuine.