How did an escaped slave live in the north?

When slaves escaped to the North, they had, in theory, their freedom. After the passage of the Fugitive Slave Act in 1850, slaves had to be more guarded about how they lived if they stayed in the North.
Prior to the passage of the Fugitive Slave Act, escaped slaves still had to be careful about how they lived their lives. There was a provision in the Constitution that said that slaves who ran away would not be free. This was known as the Fugitive Slave Clause. The Fugitive Slave Act of 1793 stated that slave owners could search for any slave that had run away from his or her owner. This law was not widely supported in the North. Vigilance committees would offer protection to the runaway slaves. These groups also assisted escaped slaves in trying to find work and find a place to live. However, runaway slaves still had to be careful if they continued to live in the North.
Once the Fugitive Slave Act was passed in 1850, slaves needed to be even more careful. Northerners were required by law to capture and return runaway slaves to their owners in the South. Federal commissioners would handle cases dealing with runaway slaves. These commissioners were paid more if they returned a runaway slave than if they freed a runaway slave. As a result, many runaway slaves went to Canada, where they would be completely free. The runaway slaves who stayed in the North had to live a low profile lifestyle in order to avoid being recaptured.
https://docsouth.unc.edu/neh/grimes25/summary.html

https://history.howstuffworks.com/historical-events/underground-railroad3.htm

https://www.history.com/topics/black-history/fugitive-slave-acts