How to call a function from another blueprint?

I have a function in widget blueprint and I want to call this function from level blueprint. How can I do this?

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Hello REG Ghost!

You need to create your widget before call a function inside of it!

Thank you Nachtmahr!

And this video is really essential! I saw it so many times!!

Thank you!

Aztecco is correct I just want to leave that link here for you =)