Save

Save["filename", symbol] appends definitions associated with the specified symbol to a file.

Save["filename", "patt"] appends definitions associated with all symbols whose names match the string pattern "patt".

Save["filename", "context\"]` appends definitions associated with all symbols in the specified context.

Save["filename", {object1, object2, …}] appends definitions associated with several objects.

Examples

Define a function and save it:

f[x_] := x^2
Save["myfile.wl", f]

Save multiple definitions:

Save["defs.wl", {f, g, h}]

Please visit the official Wolfram Language Reference for more details.