The tableselect type creates a table with checkboxes or radio buttons to allow a user to select either single or multiple rows within a table. You need to provide the #header attribute as an associative array of columns and #options as an array of values, each containing an associative array mapping a value to the key of the #header column. In addition, you can provide the following optional attributes:

• #empty: The value to display if the table has no options
• #multiple: Tells whether a user is able to select multiple values; it defaults to TRUE
• #js_select: Tells whether a select all checkbox should appear in the header, it defaults to TRUE

Consider this example:

$form['table'] = array( 
  '#type' => 'tableselect', 
  '#header' => [ 
    'column_one' => $this->t('Column one'), 
    'column_two' => $this->t('Column two') 
  ], 
  '#options' => [ 
    [  
      'column_one' => $this->t('Row'),  
      'column_two' => $this->t('One') , 
    ], 
    [  
      'column_one' => $this->t('Row'),  
      'column_two' => $this->t('Two'), 
    ], 
    [  
      'column_one' => $this->t('Row'),  
      'column_two' => $this->t('Three'), 
    ], 
    [  
      'column_one' => $this->t('Row'),  
      'column_two' => $this->t('Four'), 
    ], 
    [  
      'column_one' => $this->t('Row'),  
      'column_two' => $this->t('Five'), 
    ], 
  ], 
);