Hello Neil Matan
I hope this code is helpful for you

size = fields.Integer(string="Size(Tag1)")
type = fields.Char(string="Type")
concate_data = fields.Char(string="Contact Data", compute="_compute_value")

@api.depends('size', 'type')
def _compute_value(self):
for rec in self:
rec.concate_data = str(rec.name) + " " + str(rec.type)

Thanks & Regards,
Email: odoo@aktivsoftware.com
Skype: kalpeshmaheshwari