INVITATION LETTERS FOR APPLYING TOURIST VISA

I am visiting my girlfriend in China, I am staying in a hotel for 7 nights which I have booked in both our names as she is coming to stay with me while we visit some places of interest after 7 nights we are travelling to visit her family in another city but we are staying again in another hotel for 6 nights booked in both our names, my question is does she need to send me a letter of invitation ?
The Visa I will be applying for is an L type.