Use the default buttons to switch the selection mode

// Switch to the hand selection mode
<SwitchSelectionModeButton mode={SelectionMode.Hand} />

// Switch to the text selection mode
<SwitchSelectionModeButton mode={SelectionMode.Text} />

import { SelectionMode } from '@react-pdf-viewer/selection-mode';

// Your render function
const selectionModePluginInstance = selectionModePlugin();
const { SwitchSelectionModeButton } = selectionModePluginInstance;

return (
    <div
        className="rpv-core__viewer"
        style={{
            border: '1px solid rgba(0, 0, 0, 0.3)',
            display: 'flex',
            flexDirection: 'column',
            height: '100%',
        }}
    >
        <div
            style={{
                alignItems: 'center',
                backgroundColor: '#eeeeee',
                borderBottom: '1px solid rgba(0, 0, 0, 0.3)',
                display: 'flex',
                justifyContent: 'center',
                padding: '4px',
            }}
        >
            <div style={{ padding: '0px 2px' }}>
                <SwitchSelectionModeButton mode={SelectionMode.Hand} />
            </div>
            <div style={{ padding: '0px 2px' }}>
                <SwitchSelectionModeButton mode={SelectionMode.Text} />
            </div>
        </div>
        <div
            style={{
                flex: 1,
                overflow: 'hidden',
            }}
        >
            <Viewer fileUrl="/assets/pdf-open-parameters.pdf" plugins={[selectionModePluginInstance]} />
        </div>
    </div>
);