How To Enable fulltext in my Query in ES?

Question

var response = client.Search<ModelName>(s => s

.Index("indexName")

.Query(q => q

.MultiMatch(m => m

.Fields(fields => fields

.Field(p => p.Field1, 0.2)

.Field(p => p.Field2, 1)

.Field(p => p.Field3, 0.5)

.Field(p => p.Field4, 0.4)

.Field(p => p.Field5, 0.8))

.Type(TextQueryType.MostFields)

.Query(term))));