Hi this is the full code for sale order
if not record.partner_id.mobile:
raise UserError('No mobile number found for the selected partner.')
else:
# create link
target_url = "https://erp.gyeongcc.com" + record.get_portal_url()
link_tracker = env['link.tracker'].search([('url', '=', target_url)], limit=1)
if not link_tracker:
link_tracker = env['link.tracker'].create({
'title': record.name,
'url': target_url,
})

if record.state == 'sale':
# create message for WhatsApp (specific to sales order)
message_whatsapp = "Hello %s%%0AYour order *%s* amounting in *%s* *%s* is has been confirmed.%%0AThank you for your trust!%%0Alink to view: %s%%0ADo not hesitate to contact us if you have any questions." % (record.partner_id.name, record.name, record.amount_total, record.currency_id.name, link_tracker.short_url)

# create message for chatter (specific to sales order)
message_chatter = "Hello %s<br> Your order <b>%s</b> amounting in <b>%s %s</b> has been confirmed.<br>Thank you for your trust!<br>link to view: %s<br>Do not hesitate to contact us if you have any questions." % (record.partner_id.name, record.name, record.amount_total, record.currency_id.name, link_tracker.short_url)
else:
# create message for WhatsApp (specific to quotation)
message_whatsapp = "Hello %s%%0AYour quotation *%s* amounting in *%s* *%s* is ready for review.%%0AHere's the link to view it: %s%%0ADo not hesitate to contact us if you have any questions." % (record.partner_id.name, record.name, record.amount_total, record.currency_id.name, link_tracker.short_url)

# create message for chatter (specific to quotation)
message_chatter = "Hello %s<br> Your quotation <b>%s</b> amounting in <b>%s %s</b> is ready for review.<br> Here's the link to view it: %s<br>Do not hesitate to contact us if you have any questions." % (record.partner_id.name, record.name, record.amount_total, record.currency_id.name, link_tracker.short_url)

# create action for WhatsApp
action = {
'name': "WhatsApp",
'type': 'ir.actions.act_url',
'url': "https://api.whatsapp.com/send?phone=%s&text=%s" % (record.partner_id.mobile, message_whatsapp),
'target': 'new',
}

# create message for chatter
body = "<div style='background-color:#EAF4E8; padding: 10px;'><b>WhatsApp message sent:</b><br/>" + message_chatter + "</div>"
record.message_post(body=body)

Thank you very much, I have a problem with the link created. This link returns me:

http://ariano.com.ar/r/p1Z

Could it be that I'm missing the record.get_portal_url() action somewhere else?

As requested, the URL parameter of my site was wrong.
Goes perfectly!

Thank you so much!

Please find code here :-

# Header
import urllib.parse

# create message
url = "https://erp.gyc.com/mail/view?" + urllib.parse.quote("model=sale.order&res_id=%s&access_token=%s" %(record.id, record.access_token))

message = "Hello %s,
Your quotation %s amounting in %s %s is ready for review.
Here's the link to view it: %s
Regards," % (record.partner_id.name, record.name, record.amount_total, record.currency_id.name, url)