Put an underline at the point whereyou want to break the line:
Range("E2 : E" & LRow).FormulaR1C1 = "=TRIM(IF(ISERROR(FIND(""Claim Remark Codes:"",RC[-4])), _
IF(ISERROR(FIND(""ICN:"",RC[-4])),R[-1]C,IF(ISERROR(FIND(""."",RC[-4])), _
RIGHT(RC[-4],LEN(RC[-4])-FIND(""ICN:"",RC[-4])-3),MID(RC[-4],5,FIND(""|"", _
SUBSTITUTE(RC[-4],"" "",""|"",LEN(RC[-4]) _
LEN(SUBSTITUTE(RC[-4],"" "",""""))))-1- _
FIND("":"",RC[-4])))),MID(RC[-4],FIND(""ICN:"",RC[-4])+4,FIND(""Claim"",RC[-4])-6)))"