Symbols are the entities that are not present in our keyboard like Euro(€), Empty set(∅) etc.
we can add it manually by the use of various numbers as given below:

Numbers Symbols

∀ ∀
∂ ∂
∃ ∃
∅ ∅
∇ ∇
∈ ∈
∉ ∉
∋ ∋
∏ ∏