Is there an easy way to find birth records for Philadelphia, PA for my grandmother born in 1918?
@KarenHludik, Pennsylvania, government, birth records (e.g., birth certificates) have a 105 year restriction on them: i.e., "is not classified as a public document until 105 years after the individual's birth."
However, as you are seeking a birth record for your grandmother, you do appear to qualify to apply to receive a copy of her birth certificate. There is a $20 fee associated with requesting a copy of the birth certificate; you would make this request of the Pennsylvania Department of Health, Division of Vital Records.
I will provide a link that gives you the necessary information, address, and a link to order the certificate online. This, at least, provides you with an option, if you choose to use.
If your research target was Roman Catholic, baptisms through 1921 are available and will include the date of birth.
@KarenHludik, you might try taking a look at the FamilySearch Wiki page: "Philadelphia County, Pennsylvania Genealogy". There is a Contents box at the top, left of the page. Scrolling down, through the contents, you should find 2.28.1 Births. Clicking on that is the quickest way to get to the Births section of the wiki page. There you should find record collections that may contain information for which you are searching.
@Mike357 The record set Pennsylvania, Historical Society of Pennsylvania, Births and Baptisms, 1520-1999, 4138679, is not accessible from home with a public account. We had a discussion here https://community.familysearch.org/en/discussion/comment/428929 a few weeks ago.