alexander, john born 10/08/1805 in antrim, ulster co. frances sharpe born 1/6/1818 inRathdrum wicklow co ireland the two were ma

Statutory birth registration only started in Ireland in 1864, so you won’t find a birth certificate. Prior to that you need to rely on church baptism records, where they survive.

You say that John was Church of England. (In Ireland, that’s the Church of Ireland).    There are 78 COI parishes in Co. Antrim. See:

http://www.ancestryireland.com/civil-parish-maps-for-ulster/civil-parishes-of-county-antrim/

Some of those records are on-line on pay to view/subscription sites such as rootsireland and the Ulster Historical Foundation. However many are not, and you should also know that about 40% of all early Church of Ireland records were destroyed in a fire in Dublin in 1922. The most complete set of COI records for Co. Antrim is probably the one in PRONI, the public record office, in Belfast. Their copies are not on-line and so a personal visit is required to access them. If you are unable to go there yourself, you may need to employ a researcher. I note that you have put this post under Aghalee parish. If that’s where John came from then the bad news is that according to the PRONI site, their records only start in 1811. If you have no idea where in Co Antrim John came from, then it may just be a matter of working through all those that have records for around 1805.

Note that John Alexander is a fairly common name,. There were 167 of them in the 1901 Irish census, of whom 61 lived in Co. Antrim.

http://www.proni.gov.uk/guide_to_church_records.pdf

For Rathdrum Church of Ireland, the good news is that their records start in 1706. There is a copy in the Representative Church Body (RCB) library in Dublin, and another in the National Archives of Ireland, again in Dublin. Not certain if they are on-line anywhere. You could try rootsireland (subscription).

 THANKS SO MUCH FOR YOUR R​EPLY!!! AT AN EARLY AGE JOHN ALEXANDER BOARDED A SHIP TO ONTERIO, CANADAIN LONDONBERRY...DOES THAT HELP ANY? DON'T KNOW THE NAME OF THE SHIP.

No. Sadly there are very few passenger records to Canada prior to about the 1840s.