from reportlab.lib.pagesizes import letter, A4
from reportlab.pdfgen import canvas
from reportlab.platypus import SimpleDocTemplate, Paragraph, Spacer
from reportlab.lib.styles import getSampleStyleSheet, ParagraphStyle

doc = SimpleDocTemplate("text.pdf", pagesize=A4,
                        rightMargin=72, leftMargin=72,
                        topMargin=72, bottomMargin=18)


content = []
styles = getSampleStyleSheet()

for i in range(10):
    p = Paragraph('<font size=12>{}</font>'.format(i), styles["Normal"])
    content.append(p)
    content.append(Spacer(1, 12))

doc.build(content)