converts them to uppercase

 

helloExpressionsSimple.js

import { LightningElement } from 'lwc';

export default class HelloExpr extends LightningElement {

    Name = 'Prahlad';

    lastName = 'Bandhu';

    get uppercasedFullName() {

        const fullName = `${this.Name} ${this.lastName}`;

        return fullName.trim().toUpperCase();

    }

}

helloExpressionsSimple.html

<template>

  cased Full Name: {uppercasedFullName}

</template>

Output 

cased Full Name: PRAHLAD BANDHU