Do you think it is better/more efficient to spend a lot of time in a forum to get help for issues you would not have if you would learn the basics of the programming language you're using? You should really reconsider your approach...

I know, but as I said it's a project my boss gives me with a deadline in a week and they know I have little experience in C++; so i'm stuck here trying to build something with what I know and I found online

I dont have actual time to learn c++ in a right way

Do you think it is better/more efficient to spend a lot of time in a forum to get help for issues you would not have if you would learn the basics of the programming language you're using? You should really reconsider your approach...

struct is one of the most basic things in C++:

struct Data
{
    QString data1;
    QString data2;
    ...
}

Data parametri::getValuePar()
{
    Data result;
    result.data1 = ui->pmFV->text();
    result.data2 = ui->glmF->text();
    ...
    return result;
}

I dont have actual time to learn c++ in a right way;

Then you're wrong here.

And I repeat, this give me the output I wrote in my last comment, but not in the format I need

It does not compile since QLineEdit has not function text() which takes an integer.

I'm out here.

And I repeat, this give me the output I wrote in my last comment, but not in the format I need

This does not even compile...

it was and example to let you understand the output for god sake, it's not my actual code if you have to answer pls at least try to understan what I'm writing

QString pmFV = ui->pmFV->text(123);
QString glmF = ui->glmF->text(78);

This does not even compile...

How about some c++ basics before starting with Qt

I actually dont know how to do that. It the right way I mean.

See e.g QString::append()

and this is the output in qDebug() -> 12378

create a structure where you put all these strings and implement a getter method which returns this struct.

I actually dont know how to do that. It the right way I mean. It's already been 2days i'm trying to have this :(

You should have at least a warning about this in QtCreator.

I dont, because my MainWindow start and when I try to open the Dialog the terminal just says it crashed. If I had a warning first I would see it and second my application woudnt start at all

What do you expect?

As I already said: I just want to get the texts from QLineEdit in my Dialog to my Main Window

but crashed when I click the button to open the Dialog

I think it crashes here QString value = pd.getResult();

because your non void function has no return statement. You should have at least a warning about this in QtCreator.

I'm actually have more QLineEdit value to transfer from Dialog to MW

Either create a getter method for each of them or create a structure where you put all these strings and implement a getter method which returns this struct.

When I run the project It opens the MainWindow but crashed when I click the button to open the Dialog

What do you expect? I mean - what should this do:

QString parametri::getValuePar()
{
    ui->pmFV->text();
    ui->glmF->text();
    ui->icpF->text();
    ui->gamEP->text();
}

Please learn c++ basics.

dialog.cpp

QString parametri::getValuePar()
{
    QString pmFV =  ui->pmFV->text();    
   QString glmF = ui->glmF->text();    
     QString icpF =ui->icpF->text();    
     QString gamEP =ui->gamEP->text();    
      QString icpEP = ui->icpEP->text();
    return pmFV + glmF;
}

QString parametri::getResult()
{
    return getValuePar();
}

MainWindow,cpp

void MainWindow::on_parametri_clicked()
{
    class parametri pd;
    pd.exec();
    QString value = pd.getResult();
    qDebug() << value;
}

When I run the project It opens the MainWindow but crashed when I click the button to open the Dialog

How can I do it?

Add a getter method to your dialog which returns the data you need. No need for signals/slots here.

// In MainWindow
Dialog dlg;
dlg.exec();
QString value = dlg.getResult();

// In Dialog
QString Dialog::getResult()
{
    return ui->pmFV->text();
}