styled_excel_sheet.md

import React, {Component} from 'react';
import ReactExport from 'react-data-export';
import './App.css';

const ExcelFile = ReactExport.ExcelFile;
const ExcelSheet = ReactExport.ExcelFile.ExcelSheet;

const multiDataSet = [
    {
        columns: [
            {title: "Headings", width: {wpx: 80}},//pixels width 
            {title: "Text Style", width: {wch: 40}},//char width 
            {title: "Colors", width: {wpx: 90}},
        ],
        data: [
            [
                {value: "H1", style: {font: {sz: "24", bold: true}}},
                {value: "Bold", style: {font: {bold: true}}},
                {value: "Red", style: {fill: {patternType: "solid", fgColor: {rgb: "FFFF0000"}}}},
            ],
            [
                {value: "H2", style: {font: {sz: "18", bold: true}}},
                {value: "underline", style: {font: {underline: true}}},
                {value: "Blue", style: {fill: {patternType: "solid", fgColor: {rgb: "FF0000FF"}}}},
            ],
            [
                {value: "H3", style: {font: {sz: "14", bold: true}}},
                {value: "italic", style: {font: {italic: true}}},
                {value: "Green", style: {fill: {patternType: "solid", fgColor: {rgb: "FF00FF00"}}}},
            ],
            [
                {value: "H4", style: {font: {sz: "12", bold: true}}},
                {value: "strike", style: {font: {strike: true}}},
                {value: "Orange", style: {fill: {patternType: "solid", fgColor: {rgb: "FFF86B00"}}}},
            ],
            [
                {value: "H5", style: {font: {sz: "10.5", bold: true}}},
                {value: "outline", style: {font: {outline: true}}},
                {value: "Yellow", style: {fill: {patternType: "solid", fgColor: {rgb: "FFFFFF00"}}}},
            ],
            [
                {value: "H6", style: {font: {sz: "7.5", bold: true}}},
                {value: "shadow", style: {font: {shadow: true}}},
                {value: "Light Blue", style: {fill: {patternType: "solid", fgColor: {rgb: "FFCCEEFF"}}}}
            ]
        ]
    }
];

class App extends Component {
    render() {
        return (
            <div>
                <ExcelFile element={<button>Download Data With Styles</button>}>
                    <ExcelSheet dataSet={multiDataSet} name="Organization"/>
                </ExcelFile>
            </div>
        );
    }
}

Output

Codesandbox