Remembering those who are no longer with us or can't attend your special day is really important to many couples. It is a lovely idea to take a small moment to light a candle and say a few words/poem about those who can't be present at your ceremony.
'Lighting a Candle' can represent a loved ones spirit and this candle can stay lit for the entirety of the ceremony and then can be placed in the reception room. You can have a small frame with some brief words about what the candle is representing for your guests to read. Some people choose to place the candle next to the cake during the reception or on their bridal table.
During our meeting I like to ask if there is anyone that you would like to remember/mention. I am more than happy to discuss the many options available to find the most suitable one for your particular ceremony.