[{_id:1,f1:"senior",f2:"manager"},{_id:2,f1:"junior",f2:"manager",},{_id:3,f1:"fresher",f2:"developer"},{_id:4,f1:"manager",f2:"senior"}]

db.collection.aggregate([{$addFields:{mField:{$concat:["$f1"," ","$f2"]}}},{$addFields:{matchResult:{$and:[{$regexMatch:{input:"$mField",regex:"senior",options:"x"}},{$regexMatch:{input:"$mField",regex:"manager",options:"x"}}]}}},{$match:{matchResult:true}}])