I miss a default value...I replace:

explicit Worker(QObject *parent = nullptr, int variable);

by:

 explicit Worker(QObject *parent = nullptr, int variable = 0);

And everything start working, there is my sample code for future references to noobs like me.

mainwindow.cpp

        QThread* threadtest = new QThread;
        Worker* worker = new Worker(nullptr, 100);

        worker->moveToThread(threadtest);
        connect(worker, SIGNAL (finished()), threadtest, SLOT (quit()));
        connect(worker, SIGNAL (finished()), worker, SLOT (deleteLater()));
        connect(threadtest, SIGNAL (finished()), threadtest, SLOT (deleteLater()));

        threadtest->start();

worker.cpp

Worker::Worker(QObject *parent, int variable) : QObject(parent)
{
    int intvar = variable;
}

worker.h

class Worker : public QObject
{
    Q_OBJECT
public:
    explicit Worker(QObject *parent = nullptr, int variable = 0);
...
...
...

I miss a default value...I replace:

explicit Worker(QObject *parent = nullptr, int variable);

by:

 explicit Worker(QObject *parent = nullptr, int variable = 0);

And everything start working, there is my sample code for future references to noobs like me.

mainwindow.cpp

        QThread* threadtest = new QThread;
        Worker* worker = new Worker(nullptr, 100);

        worker->moveToThread(threadtest);
        connect(worker, SIGNAL (finished()), threadtest, SLOT (quit()));
        connect(worker, SIGNAL (finished()), worker, SLOT (deleteLater()));
        connect(threadtest, SIGNAL (finished()), threadtest, SLOT (deleteLater()));

        threadtest->start();

worker.cpp

Worker::Worker(QObject *parent, int variable) : QObject(parent)
{
    int intvar = variable;
}

worker.h

class Worker : public QObject
{
    Q_OBJECT
public:
    explicit Worker(QObject *parent = nullptr, int variable = 0);
...
...
...

Otherwise, that's correct.

What error do you get ?

Worker* worker = new Worker(nullptr, 10);

w.cpp

Worker::Worker(QObject *parent, int variable) : QObject(parent)

w.h

    explicit Worker(QObject *parent = nullptr, int variable);

Can you please sample some code? I already try but I don't know how to do it and i end every time with errors.

thanks

You have to declare a constructor that takes these parameters and not only the "QObject *parent".

in mainwindow.cpp

...
QThread* threadtest = new QThread;
MyWorker *worker = new MyWorker(param1, param2, ...);
...

in worker.cpp

...
Worker::Worker(QObject *parent) : QObject(parent)
{ 
   
}
...

in worker.h

...
public:
    explicit Worker(QObject *parent = nullptr);
...

I Have no idea how to handle the parameters in worker.cpp and worker.h files to be able to receive them.
How can I do it?

MyWorker *worker = new MyWorker(param1, param2, ...);

Or you can pass them later using signals/slots.