How To Change itemsPerPageLabel in mat-paginator in Angular 6+

Create a new TypeScript file and add a function that is exported and returns a MatPaginatorIntl object.

To modify the labels and text displayed, create a new instance of MatPaginatorIntl and include it in a custom provider - Angular Material - Paginator > API

CustomPaginatorConfiguration.ts

import { MatPaginatorIntl } from '@angular/material';

export function CustomPaginator() {
  const customPaginatorIntl = new MatPaginatorIntl();

  customPaginatorIntl.itemsPerPageLabel = 'Custom_Label:';

  return customPaginatorIntl;
}

Then add it to app.module.ts:

import { MatPaginatorIntl } from '@angular/material';
import { CustomPaginator } from './app/CustomPaginatorConfiguration';

@NgModule({
  // ...
  providers: [
    { provide: MatPaginatorIntl, useValue: CustomPaginator() }
  ]
})

You can also set the setting for a particular component like:

import { CustomPaginator } from './CustomPaginator';
import { MatPaginatorIntl } from '@angular/material';
/**
 * @title Paginator
 */
@Component({
  selector: 'your_component',
  templateUrl: 'your_component.html',
  providers: [
    { provide: MatPaginatorIntl, useValue: CustomPaginator() }  // Here
  ]
})

StackBlitz

 @ViewChild(MatPaginator, { static: true }) paginator: MatPaginator;

  ngOnInit() {
    this.paginator._intl.itemsPerPageLabel="Test String";

  }

After declaring paginator, this text can be modified in ngOnInit()

Another way to achieve the result.

App and component modules define MatPaginatorIntl as providers

  providers:[
    MatPaginatorIntl
  ]

Import MatPaginatorIntl, declare on the construtor and inside ngOnInit define the next text.

import { MatPaginator, MatPaginatorIntl } from '@angular/material/paginator';

  constructor(
    public _MatPaginatorIntl: MatPaginatorIntl
  ) { }

  ngOnInit() {
    this._MatPaginatorIntl.itemsPerPageLabel = 'your custom text 1';
    this._MatPaginatorIntl.firstPageLabel = 'your custom text 2';
    this._MatPaginatorIntl.itemsPerPageLabel = 'your custom text 3';
    this._MatPaginatorIntl.lastPageLabel = 'your custom text 4';
    this._MatPaginatorIntl.nextPageLabel = 'your custom text 5';
    this._MatPaginatorIntl.previousPageLabel = 'your custom text 6'; 
  }