iframe tag can be used to display PDF File from Static Resource using Lightning Web Component(LWC) in Salesforce.

Sample Code:

HTML:

<template>
    <iframe src={SamplePDFURL} height="100%" width="100%"></iframe>
</template>

JavaScript:

import { LightningElement } from 'lwc';
import SamplePDF from '@salesforce/resourceUrl/SamplePDF';

export default class ShowPdfFile extends LightningElement {

    SamplePDFURL = SamplePDF;

}

JS-meta.xml:

<?xml version="1.0" encoding="UTF-8"?>
<LightningComponentBundle xmlns="http://soap.sforce.com/2006/04/metadata">
    <apiVersion>52.0</apiVersion>
    <isExposed>true</isExposed>
    <targets>
        <target>lightning__Tab</target>
    </targets>
</LightningComponentBundle>

Static Resource:

Output: