https://angular.io/guide/component-interaction#pass-data-from-parent-to-child-with-input-binding

sport-category.component.ts

import { Component, OnInit, Input, Output, EventEmitter } from '@angular/core';
import { BoardService } from '../../services/board/board.service'

@Component({
  selector: 'app-sport-category',
  templateUrl: './sport-category.component.html',
  styleUrls: ['./sport-category.component.scss']
})
export class SportCategoryComponent implements OnInit {y
  @Input() parentForm // input decorator
  @Input() fieldof
  list
  constructor(
    private boardSvc: BoardService
  ) {
    boardSvc.getSportsCategory().subscribe(sc => this.list = sc)

  }

  ngOnInit() {
  }

  pickedSport ($e) {
    this.parentForm.patchValue({
      [this.fieldof]: $e.detail.value
    })
  }

}