The Serialization standard library package is probably what you’re looking for.
using Serialization
my_data = Dict(:a => 1, :b => [1, 2, 3])
serialize("my_data.jls", my_data)
my_data_from_serialized = deserialize("my_data.jls")
@assert my_data == my_data_from_serialized
Also of note, if the object you want to serialize has any custom data types contained within it, you’ll want to load up the modules with those data types prior to deserializing them.