I found the answer
The following steps must be executed to allocate to a customer field in new GL FI allocations
Step1-(OXK3) Add customer fields to the coding block.
Step2-(FAGL_GINS)Add the new custom fields to the FAGLFLEXT table.
Step3-(SE11) Create value and text table for the new fields added.
Step 4-(SE16n) Maintain products and distribution channel table.
Step 5- (GLGCS1) Add the new fields in the master data check.
Step 6-make the new custom fields as optional entry in the field status group variant for postings and also open the fields for corresponding posting keys.
Step 7-(GLGCA6) maintain Field usage for distribution.
Step 8-update customer fields to the required ledgers
now create a distribution cycle FAGLGA31 and execute it using FAGLGA35