Class HorizontalRule

const doc = DocumentApp.getActiveDocument();
const documentTab = doc.getActiveTab().asDocumentTab();
const body = documentTab.getBody();

// Append a styled paragraph.
const par = body.appendParagraph('A bold, italicized paragraph.');
par.setBold(true);
par.setItalic(true);

// Retrieve the paragraph's attributes.
const atts = par.getAttributes();

// Log the paragraph attributes.
for (const att in atts) {
  Logger.log(`${att}:${atts[att]}`);
}

const doc = DocumentApp.getActiveDocument();
const documentTab = doc.getActiveTab().asDocumentTab();
const body = documentTab.getBody();

// Obtain the first element in the active tab's body.

const firstChild = body.getChild(0);

// Use getType() to determine the element's type.
if (firstChild.getType() === DocumentApp.ElementType.PARAGRAPH) {
  Logger.log('The first element is a paragraph.');
} else {
  Logger.log('The first element is not a paragraph.');
}

const doc = DocumentApp.getActiveDocument();
const documentTab = doc.getActiveTab().asDocumentTab();
const body = documentTab.getBody();

// Remove all images in the active tab's body.
const imgs = body.getImages();
for (let i = 0; i < imgs.length; i++) {
  imgs[i].removeFromParent();
}

const doc = DocumentApp.getActiveDocument();
const documentTab = doc.getActiveTab().asDocumentTab();
const body = documentTab.getBody();

// Define a custom paragraph style.
const style = {};
style[DocumentApp.Attribute.HORIZONTAL_ALIGNMENT] =
    DocumentApp.HorizontalAlignment.RIGHT;
style[DocumentApp.Attribute.FONT_FAMILY] = 'Calibri';
style[DocumentApp.Attribute.FONT_SIZE] = 18;
style[DocumentApp.Attribute.BOLD] = true;

// Append a plain paragraph.
const par = body.appendParagraph('A paragraph with custom style.');

// Apply the custom style.
par.setAttributes(style);