Using button in custom cell from another ViewController

I have to segue another class

What do you mean exactly ? You want to segue from VC1 (which contains table and cells) to another VC ? Is it "I have to segue TO another class"

If I understand correctly your question, you should:

• create a segue from the VC1 which contains TableView to the destination segue. Create from VC1, NOT from the cell.
• Give it an identifier such as "VC1toVC2" (of course, find a more explicit name)
• create a var selectedCell : Int? in VC1
• in VC1, use willSelectRow to know which cell is to be selected (this will be called when you tap the button in the cell)

    func tableView(_ tableView: UITableView, willSelectRowAt indexPath: IndexPath)  -> IndexPath? {
        
        selectedCell = indexPath.row 
        return indexPath
    }

• create the IBAction for the cell button

    @IBAction func goNext(_ sender: UIButton) {
            self.performSegue(withIdentifier: "VC1toVC2", sender: self) 
     }

Then in prepare, use selectedCell to figure content as needed and pass the appropriate data.

    override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
        
        if segue.identifier == "VC1toVC2" {
            if let destinationController = segue.destination as? VC2ViewController {
                destinationController.someContent = dataInVC1[selectedCell] // I assume the data are in such an array, but that depends on the definition of VC1
            }
        }

So does it work now (you marked the answer as correct) ?

You can in fact find the indexPath of the cell in which the button is.

A simple way is

• to set a tag for each cell, equal to its row (if there is a single section ; for multi section, you should multiplex the row with 1000*section for instance).
• in the button action, call its superView (you may have to call superview.superview until you reach a cell class or nil).
• check it is a cell and of the correct type.
• find its tag and rebuild the indexPath (or use row directly).