Most couples feel that a civil or just non religious ceremony is a dry, unromantic formality and prefer to celebrate their love in a personalised and more romantic way.
The blessing can be done into a Church or a family Chappel or in a garden, the difference from a symbolic ceremony and a blessing is there is a spiritual connotation and it is conducted in a more religious way. It doesn’t to be Catholic or Christian or any specific religion.
Your faith plays an important role in a blessing, you are committing to one another and spirituality is something that link one to another.
You may whish that your beliefs are part of the ceremony and have a special blessing by a Ministrant that represent the Divine. Blessings are not bound by strict religious constraint, it is possible to incorporate different elements for the main principle of love and tolerance.
The blessings involve spiritual readings of a specific religion, song and a prayers, it is very flexible and it is always customize by the celebrant that usually is a Ministrant or near to a specific religion. We can even consider a blessing the marriage in the Catholic church without any legal implication or paperwork.