The CoE - central to the entire Anglican Communion of 85 million believers across 165 countries - does not allow same-sex marriage, standing by its teaching that marriage is between a man and a woman.
But the church has been wrestling with ways to make people in the LGBTQ community feel more welcome, and it apologised in January for the "hostile and homophobic response" some had faced.
Wednesday evening's vote, following years of often tortured debate, agreed that the trial services should "be introduced soon" the Church of England said, without specifying a date.
Bishops still have to give final clearance to the prayers in the services, which are trials and not final, settled church policy.
Welby, also leader of the worldwide Anglican Communion, said he recognised that divisions remained.
"I abstained ... because my pastoral responsibility extends to everyone in the Church of England and global Anglican Communion," he said in a statement published on Thursday.
A conservative group of Anglican church leaders in Uganda, Rwanda, Brazil and other countries declared in April that it no longer had confidence in Welby over his stance on same-sex unions.
The vote, which came after nine hours of debate among bishops, clergy and laity that make up the General Synod, agreed the trial standalone services would based around texts known as "Prayers of Love and Faith".
Those were a collection of prayers, readings and other resources for a same-sex couple "who love one another and who wish to give thanks for and mark that love in faith before God", the church said.
(Reporting by Muvija M; editing by Kate Holton and Andrew Heavens)
By Muvija M
